Method of manufacturing a tube



Jan. 24, 1939. J. P. SMITH I METHOD OF MANUFACTURING A TUBE Filed Oct. 3, 1935 2 Sheets-Sheet l Jan. 24, 1939. 1 TH 2,144,899

METHOD OF MANUFACTURING A TUBE Filed 001;. 3, 1935 2 Sheets-Sheet 2 l (a G l r 52. j' .4 2-1 6' 5 5 10 Joe.

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A i z :l g6 a w t 7 Patented Jan. 24 1939 I i v UNITED STATES PATENT OFFICE METHOD .OF MANUFACTURING A TUBE John Paul Smith, Chicago, Ill., assignor to The Visiting Corporation, Chicago, 111., a corporation of Virginia Application October 3, 1935, Serial No. 43,409 6 Claims. (01. 93-94) The present invention pertains to aflbrous tube exist in part as their respective sodium alcoholcoated and thoroughly impregnated with-a celluates. lose ether, the latter serving as a matrix for the It is preferl ed to employ in the present method fibres of the tube, which matrix is itself a seamthe hydroxy-alkyl ethers of cellulose, which are less tube of cellulose. ether inwhich the fibres soluble in a weak aqueous solution of sodium hyof the fibrous tube employed are imbedded. The drate and which are precipitable by an acid, such invention pertains further to an improved process as sulphuric acid, for several reasons: (a) soluof manufacturing the improved tube. tions of the hydroxy alkyl ethers may be pre- In accordance with the present invention, in pared with greater ease and less expense than 10 its preferred practice, a thin, long-fibred paper those cellulose ethers which are soluble in organic l strip is curved about a longitudinal axis into the solvents; (b) the present process is simplified by form of a tube with overlapping longitudinal employing the iormer type; and (c) the resultant margins, the margins are pasted together (prefproduct is eminently satisfactory from the erably with a cellulose ether), and a solution of standpoint of strength, transparency and other a cellulose ether or cellulose ether compound is properties which make the improved reinforced 15 applied to the strip, either before or after it is tube highly desirable as a container for food formed into a tube; and, according to the nature products, such as sausage, meat cuts; fruits, etc. of the cellulose ether employed, the tube is passed The more highly etherified cellulose comthrough a precipitating bath and subsequently pounds which are soluble in organic solvents may :9 dried, or, where precipitation, as by means of an be deposited (after the solution has been applied acid, is not required, the tubing is subjected to a to paper, for example) by remcvingthe s lvent drying operation to remove the organic solvent. by a suitable drying operation. That is, th ellu- Solutions of cellulose ethers may be prepared lose ether, in this instance, does not require preby known processes. The, cellulose ethers are of cipitation in the ordinary sense. However, after 5 two classes, namely: (a) those which are soluble the highly etherified cellulose compound has been in organic solvents, ethyl-cellulose being an exproduced, it may be, before being placed in soluample; and (b) hydroxy-ethyl-cellulose, soluble tion, acidified to remove by-products, washed in aqueous solvents, for example in 6% NaOH with water, or with water and acid and then again solution. with water, and then dried. The material may B h cl s f thers can be made, for exthen be placed in solution in a suitable solvent. 30

a p y th t at t of a s ium at Among the solvents for the material may be mensuch as alkali cellulose, with an alkyl halide (or tioned alcohol, benzol, alcohol-benzol mixture, y y-alkyl hal de-chlorhyd m) A o g ch glacial acetic acid, chloroform, chloroformethers ay be nti d cellulose thy th r. alcohol mixture, methyl acetate, methyl alcohol 5 cellulose-hydroxy-ethyl ether, and cellulosemixture, etc,

hydroxy-propyl ether. Theaccompanying drawings illustrate the proc- The y ye of l lo can be made, ess which is preferred. In this process, a solution 0, y Combining the fl y 0f glycol of'a hydroxy-alkyl ether oi cellulose is employed directly with the alkali cellulose, and 501111210115 for impregnating and forming a, matrix for the 40 thereof, for example, in 8 Weak aqueous Solution fibres of a reinforcing fabric, preferably a long- 40 of od u hy ra e, a e S t for use in the fibred thin paper; and the paper is formed into a present process. The hydroxy-alkyl ethers of celt thoroughly i t d, th n passed 11 y be p p e f such solllfion by through a precipitating bath, then through a means of the acids, as is known in the art. Ex-' purifying water t t t r h a, water bath EJ 9 8 f 511011 solutions'alei' hydroxyethyl containing a small percentage of a hygroscopic 45 ether of c u os W a (b) agent, such as glycerine, and finally through ay o yp p ether of 02611111086, drier. The process, thus, is preferably a continu- R o H H 0 ous process by means of which a long length of CH2C tubing may be produced; and the tubing may (c) hydroxyisopropyl ether of cellulose, afterward be cut into suitable lengths for use. 5

In the drawings, which are largely diagrammatic, Fig. l is a side elevational view of appain which cases, R represents the cellulose radical. ratus suitable for the practice of the improved These can be dissolved in aqueous sodium hyprocess, the drier being shown brokenly and in droxide and apparently, under these conditions, section; Fig.2, abroken plan sectional view taken.

as indicated at line 2 of Fig. 1 and illustrati the manner in which seam-paste is applied to one margin of the paper strip; Fig. 3, a sectional view of the improved tubing; Fig. 4, a broken vertical sectionalview on an enlarged scale showing a mandrel and attendant parts employed in the apparatus; and Fig. 5, a similar view showing the lower portion of the same mandrel and illustrating its relation to the precipitating bath.

In the illustration given, A designates a frame; B, a tubular mandrel; C, a strip of fabric, such as thin paper, which is taken from a roll 0' and formed into a tube C; D, a precipitating tank into which the mandrel B depends; E, a roller journaled in the lower portion of the tank D, about which the tube passes; F, a driven roll about which the tube passes as it emerges from the bath D; G,,a tank which may, if desired, contain additional precipitating liquid; G, a purifying water bath; G a flnal water bath containing a small percentage of glycerine; H, a lower series of rolls mounted in the lower portions of the last-mentioned tanks; I, an upper series of driven rolls mounted at considerable distance above the baths; J, a motor which,

( through the medium of suitable gearing J, drives the feedrolls mentioned and also drives pumps K and L which serve to deliver the cellulose ether solution to a seam-pasting device K and an annular coating device L, respectively; M, a forming-ring through which the tube passes from the pasting device K to the coating device L, the margins of the strip beingflrmly pasted together before the coating device is reached; and N, a dryingdevice through which the tubing is passed continuously after leaving the bath G it being noted that the section of the tubing passing through the drier is kept in inflated condition by means of an elongated isolated air body which is maintained in that portion of the tubing which is within the drier.

The present application is a continuation in part of my Patent No. 2,105,273, issued January 11, 1938. In that patent, apparatus corresponding with that shown in the drawings of the present application is fully illustrated, described and claimed; hence, it is deemed unnecessary to give 1nore than a cursory explanation of the apparatus in the present application.

The mandrel B 'is suitably supported by a bracket i and depends into the precipitating tank D. The fabric strip Cis drawn from the roll C'and passes downwardly about the mandrel and is curved into approximately tubular form, as shown in Fig. 2. The mandrel carries an adjustable member 2 adapted to serve as a hearing for one marginal portion of the strip. The

' member 2 is equipped with a gauge 2' which is of suitable form to hold the other margin of the tubing away while paste is being applied to the first-mentioned margin. The device K is in the form of a hollow head 3 with which communicates a pipe 3 through which cellulose ether paste is delivered. The head 3 has a flat end surface provided with a slot-like orifice (not showni through which the paste exudes as the strip passes downwardly between the head and the member 2. The other marginof the paper is then brought into overlapping relation and the -tub'e passes between the mandrel and the forming ring M as shown in Fig. 4, where the pasting I of the seam is completed. The tube then passes through the annular coating device L shown in -Fig. 4 and then downwardly through the prethe cellulose ether.

point, the tube is flattened and temporarily closed,

so that it will support an'internal bath 4, as

shown in Fig. 5. The bath in the tank Dis designated 5. Preferably the liquid heat within the tube (3 is such as to counterbalance the external pressure caused by the bath 5. In fact. it

ispreferred to have the level of the internal bath slightly above that of the external bath.

Precipitating fluid is supplied to the tank D in any desired manner. Precipitating fluid is supplied to the interior of the tubing C by means of an ingoing tube and an outgoing tube 1. The lower terminus of the tube 8 is slightly below the lower end of the mandrel, 'as appears in Fig. 5. Attached to the lower end of the mandrel is a blade I which tapers downwardly, but which widens downwardly also. The purpose of the blade is to cause lateral extension and flattening of the tube as the tube approaches the roller E shown in Fig. 1.

The lower end of the tube I depends into a cup 9 which is supported on a bracket 0* carried by the mandrel. The upper end of the cup 9 determines the level of the internal bath 4. A vacuum is applied to the tube 1 to continuously withdraw liquid from the internal bath as it overflows into the cup 8.

Details of the construction of the mandrel and attendant parts are unimportant for the purpose of the present application. It may be stated,

however, that the section III of 'the mandrel tion, the end portions of the bore flaring. The

eflect is to apply a wiping pressure to the seam as it passes through the ring M, but without causing thetubing to bind against the mandrel.

Briefly stated, the process is as follows: the strip C passes downwardly about the mandrel and is formed into approximately tubular form. As the tube moves downwardly continuously past the seam-pester shown in Fig. 2, a strip of paste is applied to one margin of the strip, the other margin is then brought into overlapping relation, and the pasting operation is completed while the tube passes through the forming ring M. The tube continues downwardly through the annular paste-applying device L, where a solution of hydroxy-alkyl ether of cellulose is applied. This material is sufllciently fluid to readily coat the external surface of the tubing. A measured supply of material is constantly pumped to the coating-applying device L through pipe Ii. The

supply is sufllcient to not only thoroughly coat the paper of the tube, but also cause the paper to become thoroughly impregnated. In the interval elapsing while the coated tube is from the coating device L to the bath 5 in the tank D, the paper becomes well saturated with The tubing then passes through the precipitating bath I, which contains a suitable precipitating agent, such as sulphuric acid. During passage of the tubing through this bath, precipitationof the hydroxy alkyl ether of cellulose occurs, that is, the ethercompound is precipitated from the solution which was applied to the paper tube. Bearing in mind that the solution contacts and surrounds the individual fibres in the paper, it will be understood that because precipitation. occurs in situ, the effect is to form a seamless cellulose ether set, sodium sulphate will form until a suitable balance is established.

In my above mentioned patent, the use of viscose in a process of this general character is described, and the product possesses certain advantages over known products. However, the use of cellulose ether, particularly in accordance with the preferred process described above, possesses certain advantages over the viscoseprocess. For example, the dispersion of cellulose as a hydroxy ether, in alkali,.is more stable than is cellulose xanthate. -Also, in the regeneration ofcellulose xanthate, gases are liberated which are toxic and corrosive. In the precipitation of hydroxy ethyl cellulose ether, no gases are formed. The product NaHSOr is formed, but it is no more corrosive of or injurious to equipment than is H2804.

If one employs, instead of a hydroxy-alkyl ether of cellulose, a .cellulose ether of the type which is soluble in organic solvents, the tubing may be formed in the manner already described and-impregnation of the tubing may be accomplished in the manner already described. The

' tubing may then be passed directly, if desired,

to a drier, such as the drier N.

For the purpose of producing tubes which are best adapted to serve as sausage casings, containers for meat cuts, containers for fruits, etc., the preferred process described above is recommended. The process which involves the use of cellulose ether in solution in an organic solvent as a means of impregnating a fabric tube is less desirable, both on account of greater dimculty in producing the cellulose ether and because, of greater difficulty in obtaining a uniform film or matrix of desired qualities. It may be remarkedv that casings produced by. the latter modification really are not desirable for sausage manufacture for the reason that such casings prevent, in the smoking operation, exit of moisture from the sausage and access to. the sausage of the effective ingredients of the smoke.

The coating may be applied to either or both sides of the fibrous fabric, as described inthe abovementioned patent. Ordinarily the application of a single coating suffices, since the ether solution will-pass readily through the fabric and coat all fibres, so that, in any event, the

interior surface, as well as the exterior surface, becomes coated. A less desirable method is to apply the ether coating to the fabric strip before the latter is formed into a tube.

Reference has been made to the use of a final bath containing glycerine. It should be stated that such a step may be used advantageously with respect to a tube impregnated with a hydroxy ether of cellulose, but is of doubtful utility in dealing with a tube impregnated with ethyl cellulose ether, which is insoluble in aqueous solvents.v In the case of ethyl cellulose ether, some suitable plasticizer may, if desired, be incorporated in the ether solution to be used for impregnatingthe paper. For example, it may be desirable to introduce into the solution a small percentage of dibutyl phthalate or tricresylphosphate.

Referring to Fig. 3, the paper tube C2 is shown as having an overlap seam designated II. The cellulose ether matrix is designated l2. It may be understood as being practically coincident with the paper fabric, by thickening the wall of the tube, thoroughly imbedding the fibres of the paper, sealing the seam of the tube, and at the same time providing inner and outer coatings for the paper. This will be true, even though the solution be applied (in the required amount) to one surface of the tube only, but, of course. the coating may be thickest on the surface to which the coating is applied.

The foregoing detailed description has been given for clearness of understanding only, and

no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible in view of the prior art.

What I claim as new and desire to secure by Letters Patent is:

1'. In the manufacture of impregnated tubes, a process which comprises: progressively feeding a continuous thin paper strip and bringing its longitudinal margins into overlapping relation to form a cylindrical tube, impregnating said strip with a solution of cellulose ether, and treating the distended impregnated tubing to deposit the cellulose ether in situ. I

2. In the manufacture of impregnated tubes, a process which comprises: continuously feeding through aprecipitating medium a cellulose-etherimpregnated fabric strip in tubular form having its longitudinal margins overlapped and pasted together and effecting precipitation of the impregnating material while keeping the tube distended.

3. A process as, specified in claim 2, as practiced by employing a hydroxy-alkyl ether of cellulose -as the impregnating material.

4. In the manufacture of impregnated tubes. a process which comprises: progressively and continuously feeding through a precipitating medium a fabric strip having its longitudinal margins overlapped, said strip being thoroughly impregnated with a hydroxy-alkyl ether of cellulose, and effecting precipitation of said hydroxy alkyl ether of cellulose whilethe tube thus formed isdistended.

5. In the manufacture of a coated tubing, a process which comprises: progressively and continuously forming a tube from a stripof thin fabric; progressively applying to-the tubing as formed a coating comprising a solution of hydroxy alkyl ether of cellulose and effecting impregnation of the fabric; and progressively pass- .ing the coated distended and impregnated tube through a precipitating bath.

6. In the manufacture of tubing, a process which comprises: passing a thin-walled vegetable fibre tube impregnated with a solution of an hydroxy'alkyl ether of cellulose downwardly through an external precipitating bath which affords a given .head while maintaining in said tubing an internal precipitating bath which exerts a headof pressure opposed to that of the external'bath.

. JOHN PAUL SMITH. 

